Stereo Encoder: Differences in DTX for LTV 16 kHz signal
# Basic info
<!--- Add commit SHA used to reproduce-->
- Float reference:
- Encoder (float): ceb8871fb395dc677e0a02e8dba99d36074630c2
- Decoder (float): ceb8871fb395dc677e0a02e8dba99d36074630c2
- Fixed point:
- Encoder (fixed): 339e804c7cf5c345ac74d254ad89732e1a92b399
- Decoder (fixed): n/a
# Bug description
For the BASOP encoder, the DTX segment 0:02.26 - 0:03.36 in the LTVs looks and sounds significantly different. Either there is a different CNG mode selected, or the CNG quantization is somewhat wrong. There is energy missing in BASOP.
Float:

BASOP:

# Ways to reproduce
<!--Commandline or script-->
```bash
IVAS_cod -stereo -dtx 13200 16 ltv16_STEREO.wav ltv16_STEREO_13k2bps_DTX.192
IVAS_dec stereo 16 ltv16_STEREO_13k2bps_DTX.192 ltv16_STEREO_13k2bps_DTX.wav
```
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issue